Is there anything a lightsaber cannot cut through?

Other than other lightsabers?

My penis.

The Hulk's skin.

Did you bother to watch the end of Episode I-The Phantom Menace? The force field where Qui-Gon Jinn was meditating and Obi-Wan was preparing to take down Darth Maul. Their light sabers were inpenitrable to the force field.

Mutant Rancor's skin, electro-staff(GG's bodyguard's weapon), etc...

Violent2Dope, that's not appropriate...

Other than generic plot devices, such as cortosis, no, lightsabers can cut through everything except another lightsaber, blaster shot, or powerful force field.

Mandalorian iron aswell it took exar kun beating at it a while with all of his strength before it gave.

Let's see;
Energy Bolts or Fields are impossible to cut through with a saber.

Alloys;
Mandalorian Iron(Will take awhile to cut through, but other than that, it's basically Saber resistant)
Phrik alloy
Cortosis Weave
Electrum
Sith Alchemy enhanced armor or swords
Armorweave(Protection for a very limited time)
Lightfoil(Weaker than sabers, though better than vibroblades)

Originally posted by Captain REX
Violent2Dope, that's not appropriate...

Vonduun crap armor, though give it a few blows and it'll give.

In the games you will find that other combatants (such as Mandalorians) can stand up to you with their conventional swords.

Originally posted by Spartan ll
Let's see;
Energy Bolts or Fields are impossible to cut through with a saber.

Alloys;
Mandalorian Iron(Will take awhile to cut through, but other than that, it's basically Saber resistant)
Phrik alloy
Cortosis Weave
Electrum
Sith Alchemy enhanced armor or swords
Armorweave(Protection for a very limited time)
Lightfoil(Weaker than sabers, though better than vibroblades)

As I said, weak plot devices to make the foes of Jedi "more dangerous" or "invincible."

Silly concept.

Originally posted by Light_Sith
In the games you will find that other combatants (such as Mandalorians) can stand up to you with their conventional swords.

Akk dogs from Haruun Kal have hide "thick enough" to ward off a lightsaber blow.

Originally posted by Captain REX
As I said, weak plot devices to make the foes of Jedi "more dangerous" or "invincible."

Silly concept.

Unfortunately.

also orbalisk armor

Originally posted by Tangible God
Vonduun crap armor, though give it a few blows and it'll give.

I'll give u a few blows!!!

Originally posted by Satauros
I'll give u a few blows!!!

My penis can't cut through your light saber too. 😱 😂 😆 I have the most ultimate weapon against your light saber. "The Penari Penis" 😆